DE1236533B - Heat sensitive copy sheet - Google Patents

Description

UNDESREPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

B 41m

German class: 15 k-7/05

Number: 1 236 533

File number: M 46860 VI b / 15 k

Filing date: October 18, 1960

Open date: March 16, 1967

1"

The present invention relates to a heat-sensitive copier sheet for thermographic printing Reproduction of graphic originals, e.g. B. of printed and typewritten letters, of drafts, Drawings and the like In thermographic reproduction processes, the graphic original is marked with a very strong radiation, which is absorbed differently from the original, is briefly irradiated and a visible reproduction of the thermal image obtained is generated on a heat-sensitive copier paper that is copied with the Original is in thermally conductive pressure contact. The present invention relates to a novel thermosensitive Copy sheet or paper that is useful for such a reproduction process and at which the generated image areas contain an azo dye.

Commercially available light-sensitive copier papers that contain components that produce azo dye, are widespread. When irradiating such a sheet with actinic rays through a positive original and by means of chemical treatment with an actionable liquid or a Steam a positive copy is developed using the image areas that correspond to the original from the Azo dye can be generated. In such papers, the actionable material becomes through the replaces actinic radiation, so the sheet must be stored in the dark before use. the Heat-sensitive copy sheets proposed according to the invention are practically insensitive to this against light. They can be handled and stored in the light without discoloration or the heat sensitivity is lost.

To produce azo dyes, a diazonium compound is usually produced, followed by with an azo coupling component, often in an alkaline environment, for generation of the colored product is implemented. According to another known method of manufacture A diazonium compound is first an aromatic sulfonic hydrazide with a suitable oxidizing agent oxidized. The resulting diazosulfone is then phenolic under alkaline conditions Azokupplungsbeslandteile coupled. When mixing the sulfonic hydrazide, the coupler and of the oxidizing agent in an aqueous alkaline solution or in a suitable organic solvent a corresponding dye material is therefore produced immediately.

All previously known copy sheets in which azo dyes were used work according to the Light copying processes are therefore sensitive to light. The heat sensitive copy sheet

Applicant:

Minnesota Mining and Manufacturing Company, St. Paul, Minn. (V. St. A.)

Representative:

Dr.-Ing. H. Ruschke, patent attorney,

Berlin 33, Auguste-Viktoria-Str. 65

Named as inventor:

Robert Fleming Coles, Township, Minn .;

Vsevolod Tulagin, Maplewood, Minn .;

Richard Arthur Miller, St. Paul, Minn. (V. St. A.)

Claimed priority:

V. St. v. America October 19, 1959 (847 101)

In contrast, the advantages of the purely thermographic copying process are obvious. It was so far not known, this process for the production of any colored copies by means of azo coupling components to use. Here the method according to the invention opens up extensive further Possibilities, and eliminates many of the disadvantages of the previous diazype procedures.

According to the invention, a heat-sensitive copier sheet is proposed for the thermographic Reproduction of graphic originals is suitable and that from a thin flexible sheet material and a visible heat sensitive layer. This copy sheet is characterized in that the heat sensitive layer of (a) a normally solid composite condensation compound from a heterocyclic hydrazone and one with the terminal amino group of the hydrazone reactive organic compound and (b) a normally solid organic oxidizing agent and an azo coupler component either in the form of component (a) or a portion contains thereof or as a separate component, with components (a) and (b) in physically separated, chemically convertible arrangement are kept.

The main advantage of the product according to the invention is that it can be used for long periods of time Handling and exposure e.g. B. in one

3 4

Office is neither discolored, nor is its heat - with suitable oxidizing agents as the only image -

sensitivity decreased. With this paper, generating constituents will be able to be produced and

clear, permanent copies with high contrast and that surprisingly dark and high-contrast

get sharp details. No solutions, thermal imaging surfaces can be obtained.

Fumes or vapors or similar image-developing 5 It has also been found that the above

Funds are needed for this; the use of a described hydrazone coupler compound is essential

Thermal image borrowed after thermographic dry copying are less colored than the corresponding simple one

process is for the immediate production of a mixture of hydrazone and coupler, so that the

direct, permanent copy is sufficient. copy sheet obtained in practically white form

The color or tint of an azo dye that io put and the greatest possible contrast between

can be created from a certain diazonium compound and image and background surfaces,

a particular coupler component, the compound compounds are more effective

can usually with considerable accuracy as an equal amount by weight of the hydrazone coupler

from the chemical structure of the obtained dye mixture, so that the materials are economical

be predicted. Although such predictions can be used at 15 and the initial color

many of the oxidative coupler systems that can be further reduced according to the invention of the sheet product. the

can be used according to, apply, deliver color-producing reaction apparently takes place with the

certain preferably used mixtures over compound compound faster than with the

surprisingly colored products that have a significantly individual implementation participant,

darker color than that due to the normally so on the other hand is a far greater number of

expected structure have predicted color. Compositions with separate ingredients

According to the invention can therefore be white or very composed of hydrazone and coupler than with the less easily

weakly colored copy papers are produced, accessible composite compounds are possible

when heated, such. B. borrowed at a thermographic, so that very effective copy sheets from such

see copying processes, image areas with an incomplete composition have been produced. To a

waiting to produce dark color, so that copies with typical mass belongs to S-methyl ^ -benzothiazolinon-

excellent readability can be obtained. acetylhydrazone together with an oxidizing agent

These preferably used copier papers and an azo coupler component, such as a phenol, have a further advantage in that only two naphthol, an aromatic amine, or one α-keto-converting component, namely an oxy-methylene coupler component, of which naphtholating agent and a color-producing component , like couplers, of the kind such as B. 3-hydroxy may be required. The last component mentioned 2-naphthol-acid acrylamide, preferably used, is a composite condensation product. The composite hydrazone couplers, an azo coupler component and a diazo compound, are also themselves as coupler component compounds forming component which, among the 35 parts, can be used in systems made up of three components, exposure to the oxidizing agent at the temperature reached first in thermo-in which the acetylhydrazone or similar transfer processes Settlement participants are used,
is cleaved, whereupon the constituents are converted to oxidizing agents, which contain halogen atoms bound to nitrogen atoms and again positive halogen atoms for the purpose of producing an azo dye, have become linked. However, the dye produced has been found to be particularly effective. These agents are colorless, a much darker shade than due to insoluble, high-melting solids, which was to be expected from the constituents used, and the production of normally stable, quickly visible contrast obtained in the finished copy is therefore bar more convertible, practically colorless heat significantly higher than the one to be expected. more sensitive layers.

A specific example of a compound 45 The lower melting types can also

Compound which can be used in conjunction with a suitable one, but the copier obtained

Oxidizer is an effective heat-sensitive sheet slightly less in normal handling

Copy sheet shows that a deep purple image is permanent on one, but also on more easily achievable ones

can form an essentially white background, copying temperatures are converted into the colored form

the compound of formula (I) which is called 3-methyl-50. Useful oxidizing agents include

2-benzothiazolinon-l'-hydroxy-2'-naphthoylhydrazone the N-halosuccinimides, -phthalimides, -acetanilides,

and has a melting point of 194 ° C -oxanilide, -benzamides and certain N-halogen

owns. In the cleavage and oxidation of such a benzene- and N-halotoluenesulphonamides. The N-HaIo-

Compound is a fragment of a diazo compound gene-N-alkylsulfonamide, which is between about 150 and

and a coupler component with which melts in the angular 55 200 ⁰ C and in which the halogen is chlorine,

Brackets given formulas (II) and (III) combine high resistance at room temperatures

expect that the specified coupling with quick implementation ability in copying conditions

implementation: formulas (II), (III), (IV). gung; these connections are therefore preferred

The formation of a deep purple or black-wise used. The carboxyamides are less zen image instead of a magenta image in copier 60 active and require the use of lighter oxidizing sheets, this composite compound of ready hydrazone compounds. The imides are abstained suggests that another further versus very actionable and therefore can or additional conversion takes place, more possibly only with the less reactive hydrazones wise the fragment of the diazo compound to be used with the, and it is also an unoriginal one compound compound kup- 65 have desired odor. Which preferably peeled. Regardless of the theory, however, it is always applied compound that gives excellent results found to provide effective copy sheets is N, N'-dichloro-N, N'-bis- (m-nitrobenzenesulene compound compounds together fonyi) ethylenediamine.

5 6

Another class of oxidizing agents, the paper backing, is held on permanently, is particularly useful in connection with means, where an easy to handle, rough, impenetrable Hydrazone, but no added coupler - a visible and economical product is obtained, constituent include the active quinoids. However, the coating can also be used for production Oxidizing agents such as 1,4-benzoquinone, 1,2-naphtho- 5 of a self-supporting thin film e.g. B. after a quinone and chloranil. Here, the quinone itself will be dried process in which he z. B. on dried to a hydroxy aromatic coupler component on a polished metal drum and then which is then reduced with the oxidation of the for the purpose of producing an exceptionally thin, Diazo compound produced by hydrazone couples. White non-fibrous copy sheet is peeled off from it, Other coupler components are in such masses or io not mandatory. The quinone settlement materials of a fibrous mat come in handy however, are self-colored, lending the copy sheet a copy sheet in the absence of a separate binder an undesirable particular color.

although the thermographic copying produced the relative proportions of the conversion Image areas opposite the subsurface 15 participants have proven to be insignificant, are clearly visible. This mass is therefore usually the pre- although stoichiometric amounts predominantly for dyed or colored light-sensitive give greatest effectiveness. The amount of order copy sheets useful. Inert pigments with the settlement participant must, however, be within the match or complementary hue, the settlement zone can be sufficiently large for the purpose Increasing or decreasing the color 20 desired visual change is produced. the of the sheet or white pigments to dilute the amount of binder material is also not Color can be added, however, the strength of the material is essential, provided that the mass is on or in The thermal image is somewhat reduced. the sheet or film is effectively retained and

Other classes of oxidizing agents are an effective visible change when heated which is generated in solution to convert the hydrazide-25. Also the type of binding used a diazo bond for the implementation by means has no significant effect on the Coupling in the production of azo dyes !! Usability of the copy sheet provided that are very useful. These include peroxides, which are chemically inert in the copying process Ozonides, inorganic oxidizing agents and the like. Ob- reached temperatures does not melt and in probably such substances can be applied to heat-sensitive copy sheets 30 volatile carriers, which themselves can be incorporated, many of them are not premature implementation of as implementation part difficult or even dangerous to handle or the components used in the coating heavily colored, or they may cause a bad odor.

or are in the presence of organic materials. The currently preferred form or moisture inconsistent or are otherwise composed of a heat-sensitive copier paper Way unsuitable for making good copy sheets; a thin transparent paper backing, a the quinoid and the N-halogen compounds and heat-sensitive coating and also a visual one the N-chlorine compounds, the opaque white coating on top. The heat-written therefore, sensitive coating supplies are preferably used in thermography. 40 copying processes see a clearly visible image. That

The copy sheets are usually made from a transparent paper allowing the observation of the process in which each of the conversion images as a direct copy of the graphic original and separately in extremely fine distribution also provides an effective marking surface, on a solution of a suitable resinous or poly - The later if necessary remarks attached meren binder is dispersed, the dispersions 45 can be. The surface layer creates a layer that is sensitive to heat, either in a single mixture or in separate distinct physical protection for the heat-adjoining layers on a flexible support and provides an opaque and in which the volatile, liquid visible white background against which the image support evaporates by evaporation Temperatures wide areas have a very high contrast,
is removed below the activation temperature. In some cases, the contrast can be increased by separating coatings, preferably by adding suitable inert pigments, fillers or similar parts with high conversion capability or by that in the heat-sensitive layer. Use of different binders or carriers. Other materials can also be added to the reaction participants using this process; Particular advantages are often achieved to enable different solubilities or for the purpose of 55 when fusible organic substances are incorporated to achieve improved resistance. Many fusible, weak rainstuffs for the purpose of reducing the reducing agents such as benzoin, benzoin oxime and benzil by a colored reaction participant acid, lower the required copying temperature called background color to a minimum, while at the same time using the resistance of or for other reasons. However, since a 60 anti-darkening copy sheet or single coating for application and drying requires less time for discoloration in storage or use while improving in smaller amounts. Various other fusible materials per unit area are used in the same way, it is usually advantageous to mix the dispersions settling ability of the sheet in the copying process and the mixture beforehand, if this is not possible, but without impairing the durability of the sheet is to be applied in a single coat. is improved to an appropriate extent. Additions to these The cover can be put on a carrier tape, ζ. B. in kinds but also enable the production of active form of a thin surface layer on a samer copy sheets with implementation participants who

require such high temperatures or such long reaction times in the absence of such additives that they would become technically unacceptable. Examples are benzoic acid, benzenesulfonamide, Benzamide, urea and various waxes that range between about 110 and Melting 155 "C.

The temperatures reached on the heat-sensitive layer during thermographic reproduction are difficult to measure directly, so indirect methods have been developed for this. So it has been found that copy sheets that have a highly visible change in a short-term Contact with a metal test rod that heats to a temperature between about 90 and 150 ° C has been experienced and not within about 2 hours at a temperature of about 50 ° C discolored, for the production of reproductions of typewritten letters od. The like. Are suitable in commercially available thermographic copying devices.

In many of the copy sheets proposed according to the invention, reaction participants are used, none of which melt, melt, decompose or otherwise visibly change at temperatures significantly above the uppermost test temperature determined by this method. A copy sheet e.g. B. is made from approximately equal parts by weight of 3-methyl-2-benzothiazolinone-l'-hydroxy-2'-naphthoylhydrazone with a melting point of 191 to 194 ⁰ C and N.N'-dichloro-NjN'-bis-im-nitrobenzolsulfonyO- ethylenediamine with a melting point of 178 to 18O ⁰ C, which are applied in a polymeric binder, prepared; this sheet is converted with brief contact with a heated to 12O ⁰ C metal test bar from the original white to a purplish black appearance. In a further example, a mixture of about 1 part by weight of very pure N, N'-dichloro-N, N'-bis (m-nitrobenzenesulfonyO-ethylenediamine with a melting point of 189 ° C and 1 part by weight of 3-methyl-2-benzothiazolinone -l 'hydroxy-2'-naphthoylhydrazon coated on a paper support, which is then changed color during brief contact with a heated at 140 ⁰ C metal test bar from white to dark purple with a melting point of 194 ° C in a polymeric binder. by adding about 1 part by weight of benzoin, which ^{melts at 133 to 137 D} C, the transformation temperature of the sheet is reduced to about 110 ⁰ C.

Possibly the various implementation participants or some of them make up for this Reduced melting point mixture so that melting at the test or use temperatures and then the reaction between the melted and well-mixed implementation participants. Another theory is that the tiny particles of reactants in an inconsistent state under pressure exerted by the film-forming binder as the solution dries, and that then under the action of heat and pressure the mixing and implementation of the implementable Components is effected. Regardless of the theory, according to the invention, a normal stable, heat-sensitive copier paper obtained in the thermographic copying process graphic originals according to a process in which an oxidative coupling takes place, in the form of Azo dye image areas and preferably in the form of dark colors on a white background.

The following examples serve to illustrate the present invention, but are not intended to limit it.

example 1

A mixture of 94.5 g of 3-methyl-2-benzothiazolinone hydrazone and 135 g phenyl-l-hydroxy-2-naphthoate is heated for about 1 hour in a suitable flask under reduced pressure on a molten metal bath to a temperature of 160-170 ⁰ C. until the phenol stops distilling. The hot solidified product is treated with 300 ecm of chlorobenzene, filtered, washed with benzene and petroleum ether and dried. It melts at 194 ° C and has been identified as S-methyl ^ -benzothiazolinone-l'-hydroxy-2'-naphthoylhydrazone. 18 g of this product are ground in a ball mill with a solution of 5 g of a copolymer of equal parts of styrene and isobutylene in 100 ecm of commercially available hexane.

A total of 44.3 g of m-nitrobenzenesulfonyl chloride is added in proportions to a mixture of 6 g of ethylenediamine, 20 g of triethyleneamine and 300 ecm of pyridine. After the reaction has ended, the product is obtained from water, dissolved in dilute sodium hydroxide and precipitated again by treatment with hydrochloric acid. 20.6 g of the purified precipitate obtained are taken up in a warm mixture of 150 ecm pyridine and 250 ecm glacial acetic acid, whereupon the mixture is treated with 118 g of an 18% solution of sodium hypochlorite. The filtered and washed product melts at 178 to 18O ⁰ C and N'-dichloro-N, N'-bis- (m-nitrobenzenesulfonyl) -ethylenediamine than N, been identified. 25 g of this product are ground in a ball mill with 5 g of a styrene-isobutylene copolymer and 100 ecm of heptane.

Weight units of each of the two suspensions

are thoroughly mixed together and applied in a thin even layer to map cover paper by means of a dust spreader, after which the cover is dried in flowing air at room temperature. The sheet material obtained is white in color and forms dense purple-black image areas when it is heated during thermographic copying or briefly heated with a metal test rod heated ^{to about 120 ° C.} The image areas are easily recognizable through the transparent paper. The unheated sheet will not be discolored with long storage, exposure, and normal office handling and will remain heat sensitive, but will be slightly discolored when stored at elevated temperatures under very high humidity.

By applying another opaque thin protective layer made of three parts of a titanium dioxide pigment in 2 parts of the polymeric binder on the heat-sensitive coating will appear and durability of the copy sheet is improved.

Example 2

A suspension of 20 g of benzoin (melting point 134 ° C) in a solution of 5 g of a styrene-isobutylene

9 10

Copolymer in 100 ecm heptane is converted into a black sheet and is used for thermo-

Ball mill produced, whereupon a unit of weight graphic reproduction of graphic originals

this suspension to the bar described in Example 1.

Mixture is added. The suspension is as used in the previous example

described above, applied and dried. The oxidizing agent is produced by a process

obtained copy sheet has been under difficult conditions, in which 20 g Ν, Ν'-dimethylbiphenylene sulfone

solutions resistant to discoloration and 4,4'-disulfonamide in 500 ecm hot glacial acetic acid,

provides an equally strong image with a roughly 200 ecm of an 18% sodium hypochlorite solution in

lower test temperature than that in Example 1 are added to the constant stream with stirring, the

written sheet. io mixture cooled quickly and filtered off and that

Very different proportions of the product obtained can be washed and dried,

Benzoin is used, an amount that is too small and has a melting point of 195 to 208 ° C,

However, this material provides neither with respect to the The corresponding ethylsulfonamide derivative melts

Resistance even with respect to the copying temperature at 187 to 190 ° C and provides a mass that is at a

a noticeable improvement, while excessive »5 implemented a slightly lower transition temperature

Quantities inappropriately dilute the image strength. Which will. The anilino derivatives are also useful.

Addition of very small amounts of benzoin or of. .

other reducing agents with even higher activity Example 4

However, it has grown in masses that are in the same way a persistent, high-melting derivative of

small amounts of active oxygen or so 3-methyl-2-benzothiazolinonhydrazone will initially

of other oxidizing agents, prepared by a process in which 13.5 g

Overcoming the tendency of such masses to phenyl isothiocyanate a hot solution of 18.9 g

discolor, proven successful. of the hydrazone in 200 ecm of ethanol under continuous

Appropriately, the benzoin and the stirring can be added dropwise. After color-producing reactants together with the addition has ended, the mixture is ^{heated for a further 1} _1/2 hours, the binder solution is dispersed, whereupon the white crystals obtained are filtered off, separately dispersed oxidants are washed with ethanol and petroleum ether and then added. dries. The melting point of the as 3-methyl-2-benzo-

Durable heat sensitive copy sheets are identified as thiazolinone-4'-phenylthiosemicarbazone

also with the product described in example 2 and in 30 is from 168 to 175 ^° C. 16 g of this material,

other binder solutions dispersed conversion 20 g of N, N'-dichloro-N, N'-dibenzoylethylenediamine and

tongue participants have been obtained, to which a 10 g of benzoin, as in Example 1, in solutions

aqueous solution of polyvinylpyrrolidone, which separated one of 5 g of polymer in 100 ecm of heptane

Trace of an alkylphenol-ethylene oxide condensation dispersed. Equal volume proportions of the three dispersing

product as a nonionic dispersant 35 ions are mixed with one another, whereupon the

contains a solution of ethyl cellulose in an absolute mixture obtained on paper and applied

Ethyl alcohol and a solution of a rubbery is dried. The white sheet obtained is at

Butadiene-styrene copolymer in toluene. a conversion temperature between 90 and 13O ⁰ C

... converted into a blue-green leaf and is for

α 1 e s 1 e ρ ^ ₀ th _he rn _O g _ra prii _sc hen copying useful.

A mixture of 18.9 g of 3-methyl-2-benzothiazo-Das by the method described above

linonhydrazone and 75 ecm o-dichlorobenzene is produced thiosemicarbazone is in a solution

Heated under reflux for 24 hours. The outflowing in dimethylformamide with oxidizing agents

Steam is identified as hydrazine. The implementation, surprisingly first a yellow,

mixture is diluted with xylene, cooled and then a green and finally a deep blue

filtered off, whereupon the product is obtained with petroleum ether settlement product. Colored products

washed and recrystallized from xylene. The are with the corresponding / S-Naphthylthiosemi-

white crystals melt at 260 ° C and are obtained as carbazone. Neither the corresponding semi-

3-methyl-2-benzothiazolinonazine has been identified. carbazone derivative or ethylthiosemicarbazone

Diphenyl ether, 2-aminopyridine, or other inert ones, 50 will provide such results or be used in the preparation of

High boiling liquid diluents can be added to copy sheet materials of those described in Example 4

Place of o-dichlorobenzene as a liquid to the effective kind usable,

seed regulation of the implementation can be used. Example 5

A coating mass is made according to a process

produced, in which 16 g of the above-mentioned 55 A solution of 18.9 g of 3-methyl-2-benzothiazoli-

given process produced azine, 18 g of 3-methyl nonhydrazone in 200 ecm of hot water, the 10 ecm

2-benzothiazolinon-l'-hydroxy-2'-naphthoylhydrazone, containing concentrated hydrochloric acid, is slow and

20 g of benzenesulfonamide and 25 g of Ν, Ν'-dichloro while stirring a solution of 10 g of potassium cyanate

N, N'-dimethylbiphenylenesulfone-4,4'-disulfonamide in 100 ecm of water and 50 to 100 g of ice were added.

Solutions of 5 g of the polymer in 100 cc of 60 ₂ After 7 hours of standing, the crystalline

Heptane are dispersed separately, whereupon the product is filtered off, washed and dried. It

individual dispersions in a volume ratio melts at 208 to 210 ⁰ C and is as 3-methyl

1: 1: 1: 2 are mixed together. The 2-benzothiazolinone semicarbazone has been identified.

A mixture of this compound 3-hydroxy-

a thin even layer and 65 N-2-naphthyl-2-naphthamide and an N-chloroxy

then dried at room temperature. The dationsmittel obtained could take in dimethylformamide

white thermosensitive copy sheet becomes with an immediate formation of a purple dye

Temperature between 90 and 130 ⁰ C can be dissolved in a purple. After that in the examples above

The method described are dispersions of 16 g of the semicarbazone, 24 g of l-amino-8-naphthol-4-sulfonic acid, 10 g of benzoin and 25 g of N, N'-dichloro-N, N'-bis (m-nitrobenzenesulfonyl) ethylenediamine prepared, whereupon equal parts by volume of the four dispersions are mixed together and the mixture applied to paper to produce a thermographic heat-sensitive copy sheet will.

Attachment of the hydrazone molecule to the coupler moiety in those used in Examples 1, 2 and 3 compound compounds serve to stabilize the former, 3-methyl-2-benzothiazolinone hydrazone has been found to be in the presence of separate coupler and oxidizer ingredients Proven to be practicable, so that the product obtained is too unstable for such purposes that require handling or prolonged storage. By attaching such a Hydrazone e.g. B. to the components of Examples 1 and 2 is the copy sheet obtained opposite "Fingerprints" are made sensitive, and there is local contamination of those with the Fingers when handling the touched surfaces, and furthermore, there will be a gradual darkening of the entire leaf.

Through the connection of the coupler radical with the hydrazone, the coupler effect is also in the one Connection made accessible and the effectiveness of the system in terms of the required Quantities of implementation participants improved; this method of stabilizing the hydrazone or a equivalent compound is therefore preferably used. Others a little less expedient, however however, stabilizing agents that can also be used are also accessible and exhibit because of their accessibility and benefits for other reasons; such masses are therefore also within the scope of the invention. In example 6, such a mass is explained.

Example 6

The compound 3-methyl-2-benzothiazolinonacetylhydrazon (melting point 258 ⁰ C) is prepared by a method in which 40 cc of acetic anhydride a hot solution of 20 g 3-methyl-2-benzothiazolinone hydrazone (melting point 135 ⁰ C) in 200 cc of benzene was added dropwise can be added. Together with this compound, an equal amount by weight of Η-acid, ie l-amino-8-hydroxynaphthalene-2,6-disulfonic acid, is used as the coupler component and N-chloro-N-methyl-m-nitrobenzenesulfonamide is used as the oxidizing agent. The three reactants are ground separately with the styrene-isobutylene copolymer and heptane, whereupon the dispersions are mixed with one another, applied to paper and dried as in the above examples. The copy sheet is stable under many non-critical conditions, and its durability can be improved by adding benzoin or a similar substance as described in Example 2. The sheet has a cream-like color and, when heated by the thermographic copying process, produces brown image areas which darken further when left to stand.

Analogous amide or equivalent condensation products of hydrazone and other organic products Acids such as octanoic acid, tetradecanoic acid, benzoic acid, naphthoic acid, phenoxyacetic acid and p-toluenesulfonic acid, also have a high melting point and low solubility in the for the Binder resins use solvents and provide very durable coatings for many purposes. Compared to the unmodified hydrazone, the hydrochloride salt also represents one in this respect some improvement.

Example 7

ίο A compound azine condensation compound is first prepared by a process in which a solution of 18.9 g of 3-methyl-2-benzothiazolinonhydrazone in 200 ecm of hot absolute ethanol with a solution of 20 g of 2,4-dihydroxybenzaldehyde is mixed in 50 ecm of the same solvent. This mixture is stirred Heated for two and a half hours and then cooled. The product obtained is filtered off with ethanol and petroleum ether washed and dried, one being weak

ao yellow-brown solid substance with a melting point of 240 to 243 ⁰ C is obtained, which has been identified as 3-methyl-2-benzothiazolinone-2 ', 4'-dihydroxybenzalazine. An amount of 0.05 mol of the dry solid substance is dispersed in a solution of 5 g of a styrene-isobutylene copolymer (ratio of 1: 1) in heptane by grinding for a long time in a ball mill. Separately, dispersions of benzoin and N, N'-dichloro-N, N'-bis (m-nitrobenzenesulfonyl) ethylenediamine are prepared by the same process. Equal proportions by volume of the three dispersions are mixed with one another, whereupon the mixture obtained is applied to map cover paper in a thickness of 0.004 cm in the moist state and the sheet obtained is dried at room temperature.

In the thermographic reproduction process, the initially practically white sheet becomes heated Image areas colored green.

Another sheet is made from the same ingredients, except that 1 part by volume of a dispersion of S-MethyW-benzothiazolinonacetylhydrazone is added to the 3 parts by volume of the coating mixture. The copier sheet obtained provides dense black thermal images. The sheet has an extraordinary resistance and shows no discoloration after long exposure to high humidity at a test ^{temperature of 50 ° C.}

If the 2 ', 4'-dihydroxybenzalazine in the mixture consisting of the three components is replaced by the corresponding 2'-hydroxybenzalazine derivative is replaced, a bluish green image is obtained. A A copy sheet to which a hydroxyl group-free benzalazine derivative has been incorporated supplies green picture. Also other aldehydes, such as 2-hydroxy-S-chlorosalicylaldehyde or 2-hydroxy-1-naphthaldehyde, form with the heterocyclic unsubstituted Hydrazones Compound condensation products in the manner of azines, which are used for the production heat sensitive thermographic copy sheets are useful.

Many other equivalent condensation derivatives of heterocyclic hydrazones can be searched for in a similar manner Process prepared and in conjunction with suitable oxidizing agents and optionally others Reactants for the preparation of useful thermosensitive thermographic Copy sheet materials can be used. In all embodiments, the condensation takes place through

a reaction at the amino nitrogen atom of the heterocyclic hydrazone. Accordingly, condensation reactions of the hydrazone compound are with organic sulfonic or carboxylic acids or with the corresponding acid chlorides or phenyl esters, with Isocyanates, isothiocyanates, hydrazones or with other compounds, the other with amino groups Contain reactive groups, under typical conditions for those reactions mentioned above in the Corresponding examples have been explained, suitable for the production of composite condensation products which are proposed according to the invention Copy sheets can be incorporated. If the compound compound is in the Oxidation is easily cleaved and both a diazonium fragment and a coupler fragment provides or if the oxidation produces an azo dye in some other way or if the oxidizing agent supplies an azo coupler component itself, no further coupler component is required, although another coupler may optionally be added. If in contrast to the compound Compound belongs to a coupler fragment, the compound itself can act as a coupler component serve in conjunction with an oxidizable heterocyclic hydrazone.

Since the hydrazone bond, but not the heterocyclic ring, provides the diazo group with which the coupling reaction takes place, many other similar compounds with, however, different heterocyclic structures can of course also be used in place of the 3-methyl-2-benzothiazolinone structure of the hydrazone compounds and derivatives given above will. The hydrazone compound must provide a visually distinct compound upon oxidizing and coupling and must provide the necessary physical properties for durability in the coating composition and in the copy sheet. The sulfur residue of the benzothiazolinone group can, for. B. be replaced by other radicals for which - Se -, - O -, - NCH ₃ - and - CH = CH - are examples. The benzene ring can be converted into a cyclohexane ring, it being possible for these and other cyclic side groups, which may optionally be present, to be substituted by other groups, such as by -SO ₃ H-, -OCH ₃ -, -CH, - or Cl groups .

The heterocyclic hydrazones which are preferably used therefore have the formulas (V), (VI) or (VII) in which Z represents the remaining atoms of a cyclic group; R is an alkyl group; Y one Group of formula

- S -, —Se -, —O -, —Ν—,
R HH

- C- or -C = C-

V is a group of the formula
OS

- C -, —C— or —S -

Il ο

and W is an alkyl, aryl, alkoxy, alkoxyalkyl, Aryloxyalkyl, amino, arylamino group or a substituted aryl group with or without an active one Coupling position on an aromatic ring is, with the further proviso that V is a group of formula

- C -

must be when W is an arylamino group.

Equivalent compounds in which the heterocyclic ring does not contain any cyclic substituents, are also useful and therefore are within the scope of the invention, but such compounds are usually less strongly colored azo dye reaction products and consequently in heat-sensitive copy sheet compositions are less useful.

ao Examples of certain compounds that correspond to the general formulas given above are:

S-methyl ^ -benzothiazolinontetradecanoyl-

hydrazone;

3-methyl-x-sulfo-2-benzothiazolinone hydrazone
or -acetylhydrazone (where χ is intended to indicate that the exact position of the sulfo group on the benzene ring is uncertain);

S-methyl ^ -benzoselenazolinone acetylhydrazone;

3-ethyl-2-benzooxazolinonbenzenesulfonylhydrazone;

l.S-Dimethyl-S-methoxy ^ -benzimidazolinone-

benzoylhydrazone;

S-MethyMjS.o.V-tetrahydro ^ -benzothiazolinone acetylhydrazone;

1-methylcarbostyrilphenoxyacetylhydrazone;

2-methylisocarbostyril acetylhydrazone;

3,3-dimethyl-1-ethyloxindoloctanoylhydrazone;

l-methylnaphtho- (l, 2-d) -thiazolin-2-one-acetyl-

hydrazone;

S-methyl ^ -benzothiazolinonmethanesulfonyl-

hydrazone;

3-methyl-2-benzothiazolinone acetylhydrazone;

3-methyl-2-benzothiazolinone semicarbazone;

3-methyl-2-benzothiazolinone-p-toluenesulfonyl-

hydrazone and

S-MethyW-benzothiazoline carbethoxyhydrazone.

As stated above, the composite hydrazone coupler compounds are also useful as couplers and can in fact react with the diazo component released from a portion of the composite compound by oxidation. These composite products can therefore provide both the diazo component and the azo coupler component, so that with smaller amounts of these reactive substances, durable copy sheets with improved contrast and with improved convertibility can be obtained. Examples of such composite compounds include the following compounds: 3-methyl-2-benzothiazolinone-1'-hydroxy-2'-naphthoylhydrazone;
S-methyl ^ -benzothiazolinone ^ '- hydroxy-3'-naphthoylhydrazone;

3-methyl-2-benzothiazolinone-1'-phenyl-5'-pyrazolone-3'-carbonylhydrazone;
S-methyl ^ -benzothiazolinonbenzoylacet-

hydrazone;

S-methyl - ^ - benzothiazolinon ^ '- naphthol-7'-sulf onyl hydrazone;

3-methyl-2-benzothiazolinonesalicylylhydrazone and

S-MethyM ^ oJ-tetrahydrobenzothiazolinonl-hydroxy-2-napththoylhydrazone.

To another class of compound condensation compounds involved in oxidation Self-colored reaction products provide and, due to the reduced concentration, improved resistance and increased contrast is achieved include e.g. B. the following connections:

3-methyl-2-benzothiazolinonazine; 3-methyl-2-benzothiazolinone-2'-salicylalazine; 3-methyl-2-benzothiazolinone-2 ', 4'-dihydroxybenzalazine;

S-Methyl ^ -benzothiazolinon ^ '- hydroxy-S'-chlorobenzalazine and ao

3-methyl-2-benzothiazolinone-4'-phenylthiosemicarbazone.

As noted above, are phenols, naphthols, aromatic amines, and α-ketomethylene couplers useful in these copy sheet compositions, however materials of the 3-hydroxy-2-naphthoearylamide class the azo coupler components as well as components of the composite hydrazone coupler compounds as well as constituents of compositions in which the heterocyclic hydrazone constituent and the coupler constituents are independent of one another. Significant examples of coupler components that are particularly useful in the latter kind of masses are:

2-hydroxy-3-naphthanilide;

N- (2-naphthyl) -2-hydroxy-3-napthamide; N- (2-chloro-4-methylphenyl) -2-hydroxy-3-naphth-

amide; * °

N- (2,5-dimethoxy phenyl) benzoylacetamide; l-phenyM-methyl-S-pyrazolone; 1 phenyl-3-amino-S-pyrazolone; S-acid; Η-acid; N-phenyl-J-acid; Salicylanilide;

Salicylamide;

N- (2-naphthyl) -1-hydroxy-2-naphthamide;

Ethyl 1-hydroxy-2-naphthoate; Phenyl-1-hydroxy-2-naphthoate and

4,4'-Bi-o-acetoacetotoluidide.

Many other classes of oxidizing agents discussed above can be found under under suitable conditions an oxidative coupling of heterocyclic hydrazones and azo coupler components cause. For a number of reasons, these are the organic compounds that make up a contain a positive chlorine or bromine atom bonded to a nitrogen atom, and especially the N-chlorine compounds preferably used. Typical examples of such compounds include the following Links:

Chloranil;

N-chlorosuccinimide; N-chlorophthalimide;

p-toluenesulfonechloramid-Na;

N, N'-4,4'-tetrachloroxanilide;

45 N-chloro-N-methyl-m-nitrobenzenesulfonic acid

amide;

N, N'-dichloro-N, N'-bis- (m-nitrobenzenesulfonyl) -

ethylenediamine;

N, N'-dichloro-N, N'-bis (p-toluenesulfonyl) -

ethylenediamine;

N-chloro-N-ethyl-m-nitrobenzenesulfonamide;

N, N'-dichloro-N, N'-bis- (m-nitrobenzoyl) -

ethylenediamine;

JS ^ N'-dichloro-I ^ N'-dibenzoylethylenediamine;

! ^, N'-dichloro-N.N'-diethylbiphenylene sulfone-

4,4'-disulfonamide;

! ^, N'-dichloro-I ^ N'-dimethylbiphenylene sulfone-

4,4'-disulfonamide;

HN'-dichloro-N.N'-dimethylbiphenyl-M'-di-

sulfonamide and
Trichloromelamine.

Claims (11)

Patent claims: 1. Heat-sensitive copier sheet used for thermographic reproduction of graphic originals is suitable and that of a thin flexible sheet material and a visibly heat sensitive Layer consists, characterized in that this is heat-sensitive Layer of (a) a normally solid composite condensation compound one heterocyclic hydrazone and one terminated with the amino group of the hydrazone reactive organic compound and (b) a normally solid organic oxidizing agent and an azo coupler component either in the form of component (a) or a portion thereof or as separate ones Contains constituent, the constituents (a) and (b) in physically separated, chemically implementable arrangement are kept. 2. Copy sheet according to claim 1, characterized in that the component (b) is an amide, the contains a positive halogen bonded to a nitrogen atom. 3. Copy sheet according to claim 2, characterized in that the halogen is chlorine. 4. copy sheet according to claim 1 or 2, characterized in that the component (a) is a compound compound of a heterocyclic hydrazone and a carboxylic acid, a organic sulfonic acid, an aryl thiocyanate or an aromatic aldehyde. 5. copy sheet according to claim 1 or 2, characterized in that the component (a) is a solid bis-heterocyclic azine. 6. copy sheet according to claim 1 or 2, characterized in that the component (a) is a composite compound of a heterocyclic hydrazone and an aromatic Is hydroxycarboxylic acid. 7. copy sheet according to claim 1 or 2, characterized in that the component (a) is a composite condensation compound of a heterocyclic hydrazone and one with the terminal amino group of the hydrazone is reactive coupler component. 8. copy sheet according to claim 1 or 2, characterized in that the component (b) is a solid quinoid oxidizing agent which can be reduced to an aromatic azo coupler component is. 9. copy sheet according to claim 1 or 2, characterized in that the component (a) is a compound compound of a heterocyclic hydrazone and an organic acid, component (b) is a solid organic oxidizing agent which is attached to a nitrogen atom contains bound positive chlorine aroma, and that this layer also contains a solid hydroxyaromatic Contains coupler component, which is also physically separated from components (a) and (b) chemically reactive assembly is maintained. 10. copy sheet according to claim 1 or 2, characterized in that the component (a) a compound compound of a heterocyclic hydrazone and a cyanate, which Layer contains a separate azo coupler component and also this coupler component in physically separated, with the components (a) and (b) chemically convertible arrangement is held. 11. Copy sheet according to claim 1 or 2, characterized in that the layer is benzoin or others Contains fusible additives. 1 sheet of drawings